Causes of Cracking of Seamless Steel Pipes

What are the main factors causing seamless steel pipe cracking? The main points are as follows:

1. Selection of raw materials
To save costs, some seamless steel pipe manufacturers use round steel produced by small steel mills for processing. However, the round steel produced by these small steel mills contains many impurities, bubbles, interlayers, pores, etc., which are prone to cracks after post-processing.

2. Improper heat treatment temperature control
Small manufacturers do not have professional production experience and technology. Workshop workers cannot ensure whether the heat treatment of the steel pipe is in place simply by relying on heating temperature and time. Heat treatment will change the mechanical properties of the steel pipe. However, manufacturers generally do not have clear indicators for different steel types, wall thicknesses, mechanical properties, etc., and they do not have testing equipment to determine whether the pipes meet the performance indicators required by customers.

How does PMC control production?
Each batch of steel pipes produced by PMC Steel Pipe has clear normalizing, annealing, tempering temperature, and speed indicators, and tensile tests are conducted to determine whether the product meets the performance required by customers. These data parameters serve as the basis for production to ensure the quality of customers' products and the stability of final use, rather than relying solely on the experience of a certain worker.

3. Straightening strength
Straightening is equivalent to secondary deformation. Bidirectional force is applied during straightening. If the operator is inexperienced, the straightening force is too large, and the strength of the thick-walled pipe is not well controlled, it will cause internal damage and cracks in the thick-walled pipe. This is also the reason for the later cracking of steel pipes.

4. Drawing deformation
Excessive drawing deformation will also form cracks in the steel pipe, causing the steel pipe to crack during later processing. Bright tubes have low elongation, generally 7-8%, large deformation and low elongation; small deformation and high elongation. Some small manufacturers cut corners and materials to save craftsmanship. The three deformations were changed to two search articles, thereby expanding the deformation causing excessive stress, and leading to cracking.